Identifying a Source of a Function Call and Inheriting Access Permission

A method performed by hardware logic, the method comprising:

• receiving a memory access request from a processing unit, wherein the memory access request is directed to a first memory region;
• receiving a first hardware signal identifying a first context associated with the memory access request;
• determining whether the first context has an inherited access permission for the first memory region;
• receiving an identifier of a calling context from a second hardware signal from the processing unit;
• determining whether the calling context has direct access permission to the first memory region, based at least in part upon the first context having the inherited access permission;
• and
• determining whether to allow or deny the memory access request based at least in part on whether the calling context has direct access permission to the first memory region.

An apparatus comprising:

• a first register configured to indicate direct access permission with respect to a plurality of contexts;
• a second register configured to indicate inherited access permission;
• hardware logic configured to enforce access to a plurality of memory regions, wherein the hardware logic is further configured to:
• receive an access request for a first memory region of the plurality of memory regions and an identifier of a first context associated with the access request;
• determine whether the first context has inherited access permission for the first memory region, including checking the identifier of the first context against information in the second register;
• in response to determining that the first context has inherited access permission for the first memory region, determine whether an identifier of a second context, received via a hardware signal from a processor core, has direct access permission to the first memory region according to information in the first register;
• and
• determine whether to allow or deny the access request based at least in part on whether the identifier of the second context has direct access permission to the first memory region.